On Fri, May 06, 2022 at 11:23:50AM +0200, Greg KH wrote:
On Fri, May 06, 2022 at 09:23:22AM +0100, Giovanni Cabiddu wrote:
Set to zero the DH context buffers containing the DH key before they are freed.
That says what, but not why.
Cc: stable@vger.kernel.org Fixes: c9839143ebbf ("crypto: qat - Add DH support") Signed-off-by: Giovanni Cabiddu giovanni.cabiddu@intel.com Reviewed-by: Adam Guerin adam.guerin@intel.com Reviewed-by: Wojciech Ziemba wojciech.ziemba@intel.com
drivers/crypto/qat/qat_common/qat_asym_algs.c | 3 +++ 1 file changed, 3 insertions(+)
diff --git a/drivers/crypto/qat/qat_common/qat_asym_algs.c b/drivers/crypto/qat/qat_common/qat_asym_algs.c index d75eb77c9fb9..2fec89b8a188 100644 --- a/drivers/crypto/qat/qat_common/qat_asym_algs.c +++ b/drivers/crypto/qat/qat_common/qat_asym_algs.c @@ -421,14 +421,17 @@ static int qat_dh_set_params(struct qat_dh_ctx *ctx, struct dh *params) static void qat_dh_clear_ctx(struct device *dev, struct qat_dh_ctx *ctx) { if (ctx->g) {
memzero_explicit(ctx->g, ctx->p_size);Why is a memset() not sufficient here?
Based on the previous conversation a memset() should be sufficient.
And what is this solving? Who would get this stale data?
This is to make sure the buffer containing sensitive data (i.e. a key) is not leaked out by a subsequent allocation. I will clarify it in the commit message.
Thanks,